


The Heat is On

by Piper_Halliwell1979



Category: Supernatural
Genre: Alpha Dean, Anal Fingering, Anal Sex, Biting, Bottom Castiel, Castiel in Heat, Coming Untouched, First Time, Fluff and Smut, Knotting, M/M, Mating Bites, Mating Cycles/In Heat, Mpreg mentioned, No mpreg, Omega Castiel, Omega Verse, Oral Sex, Rimming, Rough Sex, Sam Knows, Scenting, Smut, Spells & Enchantments, Supportive Sam, Top Dean, angel married, mated, slick
Language: English
Status: Completed
Published: 2017-10-01
Updated: 2017-10-01
Packaged: 2019-01-07 17:42:09
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings, No Archive Warnings Apply
Chapters: 1
Words: 2,782
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/12237606
Author URL: https://archiveofourown.org/users/Piper_Halliwell1979/pseuds/Piper_Halliwell1979
Summary: Castiel unexpectedly goes into heat and admits he is an Omega in need of an Alpha. Dean wants to help and allows Cas to cast a spell to make him exactly what Cas needs.





	The Heat is On

_ Slam! _ Cas came storming down the stairs of the bunker. He practically ripped his tie free from his neck and threw his trench and suit coat down on the war room table.

 

“Bad day at the office,  _ honey? _ ” Dean leaned against the door jamb with his arms crossed. Cas seethed and growled low in his throat. Dean could see him glisten with a sheen of sweat. Wait. Cas doesn’t sweat. “Hey, what the hell’s wrong with you?”

 

“Something that hasn’t happened in a millennia. I’m about to go into... _ estrus. _ ”

 

“Estrus? Like in heat? Like a cat? With the yowling?” Dean went to him but his hand was brushed away.

 

“Dean, it would be best if I spent the next few days in isolation.”

 

“Isn’t there anything we can do? Some magic birth control or something?”

 

“The only thing that will sate me is an Alpha angel.”

 

Dean scrunched his face in confusion. “I thought you  _ were _ an Alpha. I mean, all badass warrior.”

 

“I am an Omega. I have fought twice as hard to rank as a leader and have been judged and doubted every step if the way.”

 

“This heat thing...you’re a dude now. How are you supposed to…?” Dean gestured in the air.

 

“Copulate? I have endured these alone. I am undoubtedly resigned to a human body. I don’t think it possible to properly mate in my condition.”

 

“Cas, just tell me what you need.”

 

The angel stormed up close, deep in his personal space, nostrils flaring and eyes sharp. “I need to be full of Alpha seed and stretched open on a knot.”

 

Dean gulped. He was a little bit scared and a  _ lot _ turned on. “Knot?”

 

“Alphas have a knot that locks them into place to increase the chances of conception. It is similar to wolves and other canines. In a few hours I will become feral, only seeking to be bred and claimed. Please leave me be.” Cas turned his back to Dean and went to leave for the dungeon to lock himself away.

 

“Wait! I’m Michael's vessel. An archangel has to be an Alpha, right?”

 

Cas growled again. “Michael was. You are not Michael.”

 

“Fine. Forget it. I just wanted to help you.”

 

Cas looked back over his shoulder. “You just want an excuse to fuck me. I see how you look at me. If you seek me later I would not resist you.” Cas trudged a few steps forward. “I can cast a spell, give you the knot I crave. It will come with a price. You must be willing to claim me, mate me, and possibly breed me up with your child.” He didn’t look back again.

 

Dean sank down in a chair and put his face in his hands. Cas just called him out. Big time. Nut up or shut up. Literally. But was Cas still himself enough to make that proposition to him? It was a moral dilemma. It would require... _ talking.  _ Fuck.

 

“Sam!” The heavy clod of the Midwestern moose approached.

 

“Yeah?”

 

“We got a problem.”

 

“Okay?”

 

“Long story short, Cas is about to go in heat and he can cast a spell so I can... _ help _ him. The catch is I have to claim him and possibly knock him up.”

 

Sam’s mouth opened and closed a few times before he found the words he was looking for. “Cas is in heat? And helping him means you gotta…?”

 

“Like dogs. Literally. Says he needs a knot.”

 

“And the issue here is…?”

 

Dean did a double take. “You don’t see the issue?”

 

“Actually...no. I know you’re stupid in love with the guy so what’s the big deal? Mated for life? You practically are already. And unless he’s got some extra plumbing I don’t know about I doubt you can get him pregnant but so what? You get the husband and the kid? You make out pretty good with the deal.”

 

“Wow. You really don’t care?”

 

“Dean, you know that stuff doesn’t matter to me. You love who you love. Maybe it’s good this happened. Cas will know how you feel about him and you can get rid of the sexual tension clogging up the air.”

 

“So you’re saying get a dog dick and get angel married?”

 

“Spoken with the elegance of a true renaissance man.” Sam rolled his eyes. “It’s your decision. I’m saying I support you going after what you want.”

 

“Yeah. Good talk. I’m gonna go take a bath in Purell.”

 

***

 

Dean stood just outside the hidden doors to the dungeon. He’d paced his room, weighing the pros and cons. He went for the bottle of scotch under his bed but put it back. If he did this, one of them needed to be of sound mind. Was Cas able to consent? Did the invite earlier count? Would Cas be capable of saying no if he wanted to stop?

 

“Cas? You still you in there?”

 

“Yes, but not for long. Have you made your decision?” His voice was deeper and ragged. 

 

“If this is what you want, then I want it, too. I just need to know if it’s my Cas or heat Cas asking.” 

 

“Dean, I would have welcomed your advances long before my biological imperative to mate hit me.”

 

Dean sighed and fell back against the door. “Lay the spell on me.”

 

“ _ Verum dulcis alpha.” _

 

Dean felt nothing at first but then the hair on his body stood on end. He was hit with a scent that went all the way to his core. Something sweet but earthy. Honey? Wildflowers? Grass after it rains? Whatever it was it triggered something in Dean’s brain.

 

_ Mate.  _

 

“I’m coming in, Cas.”

 

The angel was on him in a flash. He nuzzled into Dean’s neck, scenting him. On instinct alone Dean did the same to Castiel’s bared neck. He felt the growl build low and he was  compelled to lick and bite. Cas pulled away before Dean could do more than a nip.

 

“Not yet, Alpha. You’ll know when.”

 

“But you smell so good, Omega. Fuck. Why’d I call you that?” Dean went for Cas’ lips this time in a deep kiss. He curled his fingers into Castiel’s sweat dampened hair. Cas pressed himself into Dean as close as he could get.

 

“Because I am your mate, it makes so much sense. Our profound bond, my feelings for you, it triggered my heat so you can claim me.”

 

“How do I do that?” Dean could barely keep his tongue and lips from Cas’ exposed skin. It was burning hot and slick with perspiration. He felt very overdressed. 

 

“I will present to you in submission, Alpha. You’ll take me and fill me with your seed. In that moment, when we are locked together as one, you will bite down. You will claim me as yours.”

 

“Yeah? How do you claim me back?”

 

Cas took a step away and looked at him in utter confusion. “You are already claimed. I left my mark on you when I raised you from perdition.”

 

“If I was claimed, why’d we wait till now to do something about it? I think I need a refresher, Cas. Something everybody can see and know I have a hot Omega mate.”

 

“Ohh...Dean. You’re wearing too many clothes.” Cas was back in full horny angel mode. He pressed two fingers to Dean’s forehead to get him stark naked and visibly aroused.

 

“Fuck that’s hot. Where do you want me, baby?” Dean’s pupils were dark with lust, matching Castiel’s. He didn’t think there was anything besides a desk and the concrete floor but he was more than willing to have Cas on any surface. The Alpha spell shed the last traces of inhibition he had.

 

Cas pulled him further into his makeshift nest for his heat. He’d pulled mats from the gym to cover the floor and had blankets and pillows from storage strewn about. He also had some towels handy. Once Dean was in his sanctum, he knelt down and arched his back. He’d promised his Alpha submission.

 

Dean dropped to his knees behind Cas, running the heel of his hand down Castiel’s spine. The angel moaned and his hole began to leak and glisten. “Did you lube up already?”

 

“It’s called slick, Dean. My body produces it to attract my mate and to ease penetration.”

 

Dean scented it. If anything smelled better than Cas it was this clear fluid running down his inner thighs. “Is it safe to taste?”

 

“Yes, Alpha.”

 

Dean had always been a considerate lover. He loved seeing a woman wet and open for him to taste and devour until her thighs were quaking by his ears. Cas looked just like that now so he couldn’t resist. He pulled Castiel’s cheeks apart and licked a broad stripe up his perineum to his pulsing hole.

 

Cas actually yelped at the sensation. He’d never been touched there before and definitely not like that. It gave his heat crazed body a promise of relief. “So good, Dean.”

 

The simple praise was enough to urge Dean further, delving his tongue into the tight rim and making Cas even wetter for him. The more he lapped the louder Cas moaned and arched his back. Slick kept coming until Dean had to stop. He ran his fingers through it and pressed into Cas.

 

He easily took two at the first pass, rocking his hips to fuck himself back onto Dean’s hand. His hole was aching,  _ burning _ for Dean to make him feel complete. Cas whimpered and stroked himself, hoping for an orgasm. It was fruitless. “Alpha, please. I need you.”

 

Dean used the slick covering his fingers to coat his shaft. He could already feel the the bump forming at the base. Must the be knot Cas told him about. He thumbed over it and pressed, nearly making himself come. No, this was for Cas, what his Omega  _ needs _ . He pushed his nearly purple head against Cas and it glided easily to the hilt.

 

“Yes, Alpha! Yes!” Cas cried out. He felt the nub of the forming knot against his rim and tried to back into Dean for it. He felt a strong hand on the back of his neck and stilled in total compliance. Dean drew back and slammed into him.

 

“You’ll get what you need, baby. Let me give you what you want first.” Dean gripped Castiel’s hips and snapped himself deep in hard thrusts. He was quite pleased when Cas started breathing in gasps and cum dripped from his red cock. “That’s it, Cas. Let it go. I’m here to take care of you.”

 

“Yes, Dean. Feels so good. Take me.  _ Claim _ me,” the lustful angel growled. Dean swore he saw a flash of grace when Cas looked over his shoulder. It fueled him. His pace was now brutal. His knot was getting bigger and he was close to finally coming.

 

Dean wrapped his arms around Cas’ waist and pulled him back onto his lap, driving the knot past his rim. He gnashed his teeth and bit down on Castiel’s exposed neck as cum pumped into Cas in waves. He shuddered and held his bite until it subsided.

 

When he released he saw the blood and licked the wound without thinking. Cas melted back against him and was sighing with relief and content. Dean tried to pull out but the tug of his knot made them both come again.

 

“You have to wait for your knot to go down. It’s designed to keep your seed inside me for breeding.”

 

Dean didn’t know why, but the word ‘breed’ caused him to fill with warmth. His hand went low on Cas’ stomach. He pictured him heavy with their child. Child? “Cas? Can you get pregnant?”

 

Cas’ shoulders dropped. “No. Not in this form. And not with a human.”

 

“But what about being Michael's vessel? Isn’t my bloodline part angel or something?”

 

“You sound disappointed, Dean. I would love to bear a child with you, my mate.”

 

Dean kissed close to his mating mark, which was already healing into a white scar. “Hey, we’re using each other’s names again. Is your heat over?”

 

“Three more days, Dean. But each time we couple it temporarily sates the urge. In a few hours I will need you again.”

 

Dean hugged him close from behind. He managed to get them down on their sides. “I’m right here. I’ll take care of you.” Dean stroked his sweaty mop of hair. He’d always felt protective of Cas but this new Alpha ego cranked it up to eleven.

 

“Will I stay like this? An Alpha?”

 

“I can reverse the spell after my heat if you wish.”

 

“Oh. The knot thing I can probably do without but I meant how I feel. I feel...I dunno...like I’m in love with you. Like you’re my whole world and all I want to do is take care of you and protect you. And I don’t want that to go away.”

 

Cas wiggled a little and Dean slipped out. He rolled over to face him. “You are my mate, Dean. Those feelings are yours and true. You chose me before I cast the spell.”

 

Dean nuzzled his way into a kiss. “Good. Just one more question. When you claim me back...does that make us angel-married?”

 

“Marriage is a human construct, Dean. But in a way...yes. Neither of us will desire another mate and we will instinctively protect our bond from aggressors.”

 

“So your heat is kinda like a honeymoon? Spending three days having obscene amounts of sex?”

 

Cas smiled. “When you put it that way…” He cupped Dean’s jaw for a sweet kiss.

 

***

 

Castiel’s heat flared again a couple hours later. Dean had been sitting up with his back against the wall, texting his brother the news that he was officially off the market and for Sam to leave food and a case of water outside the door. Cas writhed in his sleep until he came to with his eyes darkened by lust. He pushed Dean’s legs apart and sucked him down until was hard.

 

Dean dropped his phone and pulled Cas up into his lap. The angel sank down on him without any prep, still loose from their first round. He was hot and wet with slick and moved on Dean with ease. He bounced on the hunter’s cock hard and fast, Dean just holding him close. 

 

Cas came once and slowed his pace so Dean bucked his hips up into the fiery body. He felt his knot swell and before he buried it in his mate he bared his teeth again. This time he growled,  _ commanded _ , Cas to claim him. He locked them together as Cas bit into him. The orgasm was blinding.

 

Dean felt the warmth of Cas’ grace healing the fresh wound. A tender kiss on it made him come again. He may wind up keeping the knot just for the multiple orgasms. Cas draped himself over Dean and wrapped his legs around him.

 

“See? Just as much yours as you’re mine.” Dean smiled. 

 

Slowly the bite on his neck took effect. A sense of security he’d never known filled him. That void, the one that convinced him he’d live and die alone except for family, disappeared. It was silenced by the promise Cas made. Dean was mated,  _ married _ . Till death and beyond.

 

***

 

The first thing Dean and Cas did when they emerged from their ‘sex dungeon’, as Sam referred to it, was take a long hot shower. Cas used his grace intermittently to clean them but Dean insisted it would be more refreshing to bathe. They were a little handsy but Cas’ sex drive was back to normal.

 

They stood side by side in front of the mirror to admire their mating marks. “Should we get rings? I mean, who’s gonna know what these mean?” Dean asked.

 

“Rings? Oh...married. I suppose since we are visibly a human couple we need something tangible to express our union.”

 

“About the visibly. I decided I want to stay an Alpha.”

 

“Dean...I may not have another heat in your lifetime.” Cas tilted his head. “But, an Alpha such as yourself could begin to experience periodic ruts…”

 

Dean lit up. “And I’ll probably need my mate to help me through them…”

 

“I’m willing to make that sacrifice for you,” Cas teased.

 

They went to Dean’s room for fresh clothes and announced their return from their ‘honeymoon’ to Sam. He was all smiles knowing what they’d been up to. 

 

“So Cas is officially a Winchester now?” He asked.

 

Dean took his mate’s hand proudly. “Forever and always, right, Cas?”

 

Cas looked adoringly to his Alpha. “Always.”

**Author's Note:**

> I don't know Latin. Castiel's spell is probably nonsense


End file.
